We plan to test a single cell assay for plasminogen activator activity for detecting chemically transformed cells. Presently we are determining the efficiency of this test by mixing populations of normal Syrian hamster fibroblasts with chemically transformed fibroblasts. Subsequently we will apply this assay to Syrian hamster cells treated with the carcinogen, N-acetoxyacetylaminofluorene, to determine the rate and number of cells which acquire this phenotypic property of transformation. Also, we are investigating whether transformed cells have other specific proteases that can be used as biochemical markers of transformation. We also are examining some of the surface membrane properties of transformed and normal cells. We have found that the agglutinability of transformed cells with plant lectins can be modulated by alterations in growth conditions and are using lactoperoxidase catalyzed I125-labeling of the cell surface proteins to detect whether specific protein alterations on either the exterior or interior portion of the plasma membrane are correlated with the property of increased agglutinability of transformed cells by plant lectins. BIBLIOGRAPHIC REFERENCES: A. Martinez-Hernandez, L. M. Fink, P. K. Nakane and G. B. Pierce. Turnover of epithelial basement membrane (EBM). Fed. Proc. 34: 821, 1975 (Abstract); L. McManus, M. Naughton, D. Merrill, A. Martinez-Hernandez and L. M. Fink. HCG localization in human tumors. Proc. Amer. Assoc. Cancer Res. 16: 139, 1975 (Abstract).